Book/Report

FZJ-2019-01489

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Tiefenprofilanalytik an Dünnschichtsolarzellen auf der Basis von amorphem Silizium mittels der Massenspektrometrie zerstäubter Neutralteilchen und der Sekundärionen Massenspektrometrie

Gastel, M. (Corresponding author)FZJ*

1996
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/21685

Report No.: Juel-3248

Abstract: In tbis work thin film solar ceIls based on amorphous silicon are analyzed using SIMS (secondary ion mass spectrometry) and SNMS (sputtered neutrals mass spectrometry) with electron beam postionization. The solar ceIls consist of several layers wbich are 5 to 500 nm' thick. A typical structure is: Glass substrate / 50-500 nm TCO-Iayer (transparent conducting oxide, e.g. ZnO or SnO$_{2}$ ) / 5-10 nm p-Iayer (B-doped a-Si:C:H), 5-10 nm buffer layer (undoped a-Si:C:H) I 500 nm i-layer (intrinsic a-Si:H) / 25 nm n-layer (P-doped a-Si:H) / 500 nm metallic backside contact (Ag or Al). With SIMS and SNMS in principle a depth resolution of few nm can be reached. However, this is difficult, if thin films are buried beneath thicker ones. Therefore not the complete solar ceIls are analyzed, but layered structures that represent parts of the solar cell structure. In order to quantify the analytical results, the relative sensitivity factors (RSF) must be determined. Bulk and implantation standards are used for this purpose. For SIMS the RSFs depend on the matrix of the sample as well as on the experimental parameters during the analysis. For SNMS, the RSFs are less matrix dependent and more reproducable. Additionally to the measurements the RSFs for e$^{-}$-beam SNMS are determined by a model calculation. The agreement between calculated and experimentally determined values is good for most elements. Significant differences between measured and calculated RSFs are found for H, F and Al. The reasons for these differences are discussed. For several model systems that represent different parts of the solar cells depth profiles are acquired using SIMS and SNMS. Both methods yield complementary information: SNMS is used, where quantitative results are required, while for SIMS in general thelimits of detection are lower. Some of the investigated systems are: • The p-layer/TCO interface: Possible contaminations of the p-layer with metal atoms or of the TCO layer with hydrogen are analyzed. No significant contamination is found, but there are differences in the interface quality depending on the TCO material used (ZnO and SnO$_{2}$). In the case ofZnO the interface is sharper. • The buffer/p-Iayer and the i-layer/buffer-interfaces are also influenced by the TCO material used. The interfaces are much better defined if ZnO is used instead of SnO$_{2}$. • i-layer: The hydrogen contents of i-layers changes with the deposition parameters. In some cases the layer was found to be not homogeneous. • The i-layer/n-Iayer interface: The analysis of P near the interface is difficult due to the interference between $^{31}$p and 3$^{30}$Si$^{1}$H. Some ways to overcome this analytical problem are discussed.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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